CLN: Use next function rather than next method.

next and __next__ defined throughout
CLN: Modernize range + xrange.

Now range is always equivalent to 2.X xrange throughout (but need to
import range from py3compat to use it). Also remove range fixer from
setup.py.
CLN: Use Python 2/3 compatible iteritems.

Switches calls to `iteritems` method to use
`pandas.util.compat.iteritems`, which calls `iteritems` if it exists and
otherwise calls `items`.

CLN: iterkv --> iteritems
CLN: Change long literals to long function
add compat import in pandas/util/testing
CLN: Modernize bench

CLN: Modernize scripts

CLN: Modernize the rest of vb_suite

CLN: Modernize ez_setup.py

fix reverse list in tools/plotting

remove numliteral (long) fixer
CLN: Modernize usage of map

fixup to tests/test_frame
CLN: Change filter to any in core/format
CLN: Modernize zip

CLN: Modernize zip in bench

CLN: scripts - modernize zip
CLN: Modernize zip in finance

CLN: Modernize zip pt2

CLN: More zip and other modernization
update vb suite for py2/3 compat

attempt2 to block numliteral fixes in setup.py
CLN: Fix incorrect octals in datetime setup
remove 2to3 altogether
fix error in examples/finance
CLN: Fixup exec statement in plot directive
CLN: Modernize doc builders
2.6 reversed requires a known sequence to work
fix zip in tests/test_frame.py

fix zip addition issue in io/stata

fix zip issue in tests/test_groupby
CLN: Unicode --> six.text_type
CLN: unicode --> six.text_type